JOHANNESBURG  South African President Jacob Zuma said that former President Nelson Mandela has been admitted to hospital in Pretoria to undergo tests.

Zuma issued a statement Saturday saying that Mandela is “doing well and there is no cause for alarm.”

Mandela, 94, is frail health and has not made public appearances for a few years. The anti-apartheid icon was moved from his rural home to South Africa’s administrative capital, Pretoria.

The news of Mandela’s hospitalization comes just days after the crash of a military aircraft flying on an unknown mission near Mandela’s rural home in which all 11 people onboard were killed.

The plane was flying to a military air base in Mthatha, which is about 17 miles north of Qunu, the village where Mandela now lives after retiring from public life. South Africa’s military remains largely responsible for the former president’s medical care. However, military officials declined to say whether those on board had any part in caring for Mandela.

Mandela, 94, was imprisoned for nearly three decades for his fight against apartheid before becoming the nation’s president in the country’s first fully democratic vote in 1994.